The present invention relates to a device for driving a spindle mounting slide.
The invention relates in particular to a device for driving the spindle mounting slide in a machine tool supported by a frame and controlled by linear motors that drive the tool at high speed along one or more axes.
In modern automatic machine tools, the tool is usually mounted on a supporting element driven by linear motors along three axes which are perpendicular to each other.
Some automatic machine tools known in prior art comprise a linear electric motor which provides at least the vertical drive for the spindle mounting slide. The linear electric motor comprises a rotor, also known as primary member or simply “primary” and a stator, also known as secondary member or simply “secondary”, the primary being integral with the spindle mounting slide, and the secondary being integral with the vertical slideway of the slide.
The spindle mounting slide is usually connected to a counterweight designed to balance the slide itself during its vertical movement.
Experiments have shown that, in prior art machines of the type described above, the oscillating frequency of the system consisting of the spindle mounting slide and the counterweight, caused by the rigidity of the system itself, is incompatible with the translational motion of the mobile primary member of the linear electric motor and of the spindle mounting slide integral with it. Incompatible frequency means an oscillating frequency which makes it difficult to dampen the vibrations of the slide and may even lead to the instability of the system itself.
The aim of the present invention is to overcome the above mentioned disadvantage by providing a device used to drive a spindle mounting slide and equipped with a counterweight that does not interfere with the linear electric motor which provides the driving motion.